1. Technical Field
The present invention relates to prostate biopsy, and more particularly to, increasing the sensitivity of prostate biopsy procedures for detecting cancer.
2. Discussion of the Related Art
Prostate cancer is currently diagnosed by using transrectal ultrasonography (US)-guided needle biopsy, which is prescribed as a result of an elevated prostate-specific antigen (PSA) level or on account of the detection of a palpable nodule during a digital rectal exam (DRE). The introduction of image-guided biopsy with US substantially increased the accuracy of biopsy, resulting in transrectal US guidance becoming the universally accepted method for prostate biopsy. This increase in accuracy is compared to that of a completely blind biopsy. While transrectal US-guided biopsy is a clinically accepted method, the overall procedure results demonstrate a low sensitivity of around 60%, with only around a 25% positive predictive value. Consequently, repeat biopsies are required. For example, in more than 20% of cancer studies, there is a requirement of more than one biopsy session to reach a diagnosis decision.
Magnetic Resonance (MR) imaging can clearly depict not only the prostate gland but also its substructure including the central, transitional, and peripheral zones. T2-weighted images can demonstrate nodules in the peripheral zone. Localizing the tumor foci and the peripheral zone with MR imaging before the prostate biopsy may increase the overall cancer detection rate. In addition, functional information can be acquired with techniques like diffusion weighted imaging (DWI), dynamic contrast imaging (DCE), and chemical shift imaging (CSI) to further characterize the prostatic tumor tissue. Using this information during US-guided biopsy can improve the sensitivity of the biopsy procedure. For example, in a known technique, endorectal MR imaging findings of suspected tumor foci were used to guide the placement of needles during transrectal US-guided biopsy. By localizing suspected tumor lesions or targets on the endorectal MR image and by visually correlating the locations to US images during transrectal US-guided biopsy, the accuracy of the transrectal US-guided biopsy, aided by using MR imaging, was 67% in a study of 33 patients. The data for this study underwent a tedious visual inspection, which cannot be implemented as a clinical routine.
There exists a need to enhance the sensitivity in detecting malignant lesions during a prostate biopsy procedure.